Juglandaceae
Monoecious trees. Leaves odd-pinnately compound, alternate, straight-veined, petiolate, exstipulate. Staminate catkins elongate, solitary or fascicles; male flowers bracteate, stamens 3-numerous, anthers usually pubescent, filaments very short or absent. Pistillate flowers bracteate, terminal, solitary or in few-flowered spikes; stigmas 2, styles 2 or absent, ovary inferior, 1-locular, 1-ovulate. Fruit basically a nut covered by a dehiscent or indehiscent involucre; seed solitary, endosperm absent
Fruit with indehiscent husk and sculptured shell; ament single; pith of young branchlets chambered...........Juglans
Fruit with dehiscent or partly dehiscent husk and smooth or uneven, shell;
aments fascicled; pith of young branchlets continuous......................................................................................Carya
JUGLANS
Trees with glandular twigs and chambered pith. Leafelets 7-19, frequently falcate, median largest, pubescent or glabrate above, pubescent or glandular pubescent beneath, sessile or subsessile. Staminate flowers bracteate, pedicellate, in elongate, pendulous catkins, calyx 3-6 lobed, stamens usually numerous, filaments short or absent. Pistillate flowers bracteate sessile, solitary or in few-flowered spikes, calyx 4-parted, stigmas and styles 2, ovary surrounded by cup-shaped involucre. Fruit large, drupaceous.
Fruit subglobose; pith light brown.......................................................J. nigra
Fruit ellipsoid, subcylindric, or ovoid; pith dark brown..................J. cinerea
CARYA
Trees with glabrous or pubescent twigs and continuous pith. Leaflets 3-21, lanceolate, ovate, elliptic, oblanceolate, or obovate, usually glabrous above and pubescent or glabrate with trichomes in the vein axils beneath at maturity, terminal leaflets largest, basal smallest, acute or acuminate, serrate, base of terminal leaflet usually cuneate, or lateral oblique or rounded, subsessile or terminal leaflet petiolulate. Staminate catkins elongate, in fascicles; male flowers bracteate and with a 2-3 lobed calyx, stamens 3-10 usually 4, anthers pubescent, filaments absent. Pistillate flowers solitary or in 2-6 flowered spikes; female flowers bracteate and with 2 sesile stigmas and an ovary surrounded by a 4-lobed involucre. Fruit a nut enclosed by a tight involucre usually dehiscent along 1-4 sutures at maturity.
Fruit with indehiscent husk and sculptured shell; ament single; pith of young branchlets chambered...........Juglans
Fruit with dehiscent or partly dehiscent husk and smooth or uneven, shell;
aments fascicled; pith of young branchlets continuous......................................................................................Carya
JUGLANS
Trees with glandular twigs and chambered pith. Leafelets 7-19, frequently falcate, median largest, pubescent or glabrate above, pubescent or glandular pubescent beneath, sessile or subsessile. Staminate flowers bracteate, pedicellate, in elongate, pendulous catkins, calyx 3-6 lobed, stamens usually numerous, filaments short or absent. Pistillate flowers bracteate sessile, solitary or in few-flowered spikes, calyx 4-parted, stigmas and styles 2, ovary surrounded by cup-shaped involucre. Fruit large, drupaceous.
Fruit subglobose; pith light brown.......................................................J. nigra
Fruit ellipsoid, subcylindric, or ovoid; pith dark brown..................J. cinerea
CARYA
Trees with glabrous or pubescent twigs and continuous pith. Leaflets 3-21, lanceolate, ovate, elliptic, oblanceolate, or obovate, usually glabrous above and pubescent or glabrate with trichomes in the vein axils beneath at maturity, terminal leaflets largest, basal smallest, acute or acuminate, serrate, base of terminal leaflet usually cuneate, or lateral oblique or rounded, subsessile or terminal leaflet petiolulate. Staminate catkins elongate, in fascicles; male flowers bracteate and with a 2-3 lobed calyx, stamens 3-10 usually 4, anthers pubescent, filaments absent. Pistillate flowers solitary or in 2-6 flowered spikes; female flowers bracteate and with 2 sesile stigmas and an ovary surrounded by a 4-lobed involucre. Fruit a nut enclosed by a tight involucre usually dehiscent along 1-4 sutures at maturity.